A known conveyor of the above kind comprises a conveyor belt having links on each side thereof, i.e. at the inside and outside of the helical conveying path, which are formed as spacers serving to support one helically extending tier above the tier immediately below. In this known conveyor, a supplementary conveyor belt is employed to drive the lowest tier of the stack thereof.
Disadvantages which arise with the known conveyor are a possible deficiency in mechanical strength (as compared to a spiral conveyor driven throughout its height by an internal drum or capstan) and the inability to gain access to the product being conveyed at an intermediate point in the helical conveying path. However, the above-described known arrangement has the advantage of being compact in the vertical direction, i.e. in the height of the stack relative to the length of the conveying path.
It is an object of this invention to provide a helical conveyor system which, substantially without loss of the afore-mentioned compactness, at least materially reduces the stated disadvantages of the known arrangement.